Posted
by
samzenpuson Wednesday September 22, 2010 @09:51PM
from the listen-to-the-law dept.

GovTechGuy writes "The FCC's agenda for Thursday includes a vote on the final rules for unlicensed devices making use of unused TV spectrum known as 'white spaces.' Industry and lawmakers have predicted the opening up of the white spaces could result in the biggest leaps forward in wireless technology in the past 25 years. Among the benefits is so-called 'WiFi on Steroids' which allows a large number of users within a 50-mile radius to tap into a single high-speed broadband connection for the same price as a traditional WiFi router. The FCC is expected to approve the move, but Google and other companies warn that the devil is in the technical details of the rules."

Let's hope these types of changes lead to widespread distributed networking among members of the public.

I'm tired of having to choose between two or three effective local monopolies for internet access, and still having to put up with bandwidth-to-price ratios that are in the dark ages compared to many other developed nations.

It will be CB radio all over again. 40 channels of everyone trying to talk over everyone else. It will die in obscurity with nobody using it, because they've moved to something else. Think about how many people live in the 50 miles surrounding where you live.

Don't think so two dimensionally. How cool would it be to have wifi on commercial airliners that weren't based on the plane? Astronauts will be able to use it from space! Or, if you need it there, up to 50 miles straight down! Finally, Internet for the mole people.

There's a few important technical differences between this and CB. First, the current protocols are *designed* to make multiple people "talking" over each other. It reduces the bandwidth, but it doesn't break things like for analog voice. It's now possible to computationally "steer" the transmission and reception so that you can have multiple users in different locations that aren't actually talking interfering with each other.

>>>the current protocols are *designed* to make multiple people "talking" over each other.

Code Division Multiplexing (CDMA). That's very effective for voice calls. A 20 Mbit/s 6 megahertz wide TV channel can carry five thousand 4 kbit/s voice calls, but of what value is that for internet? Assign 1 Mbit/s to each data user and you only have room for twenty people. Seems very impractical to me, and a wired solution (upgrading phonelines to DSL) seems like a FAR better solution to our rural users.

With CB, you have to listen to everyone else's banter. Communications are broadcast, by definition, to anyone else whose particular squelch setting and receiver sensitivity will allow them to receive it. It is easy for one party in one conversation to step all over another party in a completely different conversation, while being completely unaware of it.

There are no PL tones [wikipedia.org] on CB to limit unintentional interference and distractions, just different channels.

But I hasten to say that things have moved on:

We now live in a world where communications are neither so rude, nor so limited.

It is now trivial to determine the precise sender and recipient of a transmission (hello, IP [wikipedia.org]). It is trivial to ratchet down output power, automatically, such as to very nearly speak only to those who you intend to speak to. And it's possible to share a band, due to things like CDMA [wikipedia.org], TDMA, [wikipedia.org] and OFDM [wikipedia.org].

None of this exists on CB.

And when mesh networking [wikipedia.org] enters the picture, things become even less like a CB.

The acceptance of a white-space provision by the FCC, no matter what modern technology it consists of, will be a boon for communications amongst a populace -- including the torrenters and the porn mavens, as well as the web browsers and the Facebookers.

To think otherwise is to disregard everything, so far, that the Internet has brought to us, as well as everything that has been learned about RF communication over the past few decades.

Just curious - are there any projects currently running on regular wifi devices that would be "supercharged" once this took off? Like if 5000 people in a 20 mile radius installed these devices is the software out there to build them into an adhoc mesh network anyone could hook into?

The Aloha Net was a predecessor of ether net.
The developers of ether net traveled to the
University of Hawaii to learn how to make
ether net from the technology of packet switch radio.

So my point is this adhoc packet switched radio networking
predates all of the Internet protocols
we use today.

To make this work, the FCC will have to develop the rules for devices to interact.
That is the part that Google is warning us about. "the devil is in the technical details of the rules." Bad rules and the th

Don't worry... These claims are Bogus.. Nothing but snake oil..'WiFi on Steroids' which allows a large number of users within a 50-mile radius to tap into a single high-speed broadband connection for the same price as a traditional WiFi router.

Sounds like the car that runs on water... The IPhone 4 not having an antenna problem, people are just holding it wrong.. and Timmy at the bottom of a well..

A packet switched radio will not have people talkingall over each other. But the low bandwidth in the TV bandswill not allow the types of bandwidth we need in today's environment.

And your right the low bandwidth long range channels (TV)will saturate with people trying to get a clear channel.What we need are high bandwidth short range channels.Something like 5 to 10 mile 300 channels of 2-3 gig each.

With this first thing your system does is find a low usechannel and sends to a host, a roof top, about 5 mile

I'm tired of having to choose between two or three effective local monopolies for internet access, and still having to put up with bandwidth-to-price ratios that are in the dark ages compared to many other developed nations.

I'm with you on this! I can overpay for AT&T DSL (no Uverse) or Time Warner Cable, or pay out of a lower orifice for slow cellular technology (no 3G available at home). It would be a dream come true to have some real competition for internet access and/or television service.

It seems to me that a hub and spoke model would be more efficient and secure than a random net. I believe oligopolies can generally be defeated with some common-sense regulation - perhaps requiring companies to rent out any wires that run under public land?

It seems to me that a hub and spoke model would be more efficient and secure than a random net

Not always. Hub and spoke means that leaf nodes in the tree are often geographically close. For example, I can see a campus building from my house, which has a machine in it that I have an account on. It's about a mile, maybe a mile and a half away. When I run a traceroute, I find that the packets are going via London (a few hundred miles away), because that is the closest peering point between JANET and my ISP's network. If I pointed a directional antenna in the right direction, I'd be able to receiv

Something similar seemed to be approved in November 2008. Anyone know why it didn't have any impact? As far as I can tell a bunch of tech companies complained that the requirement to listen for existing broadcasters, or looking up a database, was to expensive to implement in devices, and a bunch of existing broadcasters complained about interference. What will be different this time around?

This is the same issue on it's second or third go-around. I'm sure the rules for using the spectrum have been updated to take in the latest complaints, but that's probably about it.

It's time for the FCC to open this up and see what happens. Rules are in place. I'm sure they'll be adjusted as this goes. Let's use the spectrum and start dealing with some real issues instead of "possible interference" and horror stories.

Uh. Hello? The spectrum is already being used. By TV (channels 2-51) and FM Radio (sits between channels 6 and 7). There are empty channels if you live west of the Mississippi, but not along the east coast which is already assigned for Broadcast Video/Music and very, very full.

Because I don't want my Free TV killed. Because I can't afford to spend ~$1000/year to get CATV. That's why..

>>>Your free TV will not go anywhere.

The FCC has a plan right now, endorsed by our president, to shrink TV from 50 to 25 channels. It used to be 83 channels but they keep nibbling-away piece after piece, the same way RIAA/MPAA is using the ACTA treaty to nibble-away your right to backup your personal CD/DVDs. In another five years

And also because I don't want tv shows/movies/news LOCKED UP behind a paywall (where you have to subscribe to Comcast or ATTT Wireless to gain access to the programming).

And they're going after torrent sites with ACTA, it seems (if I'm interpreting the MPAA's recent query about using ACTA to shut down Wikileaks correctly.) Does anyone else besides me and the Commodore see a pattern developing here?

25 channels, assuming every other one can be used in an area, is still 12 channels. That's 24 720p HD channels for your area. More than 24 channels if some choose to multicast 480i along with the HD channel or by themselves.

How much free TV are you entitled to? Are you entitled to more free TV than someone living in Wyoming?

The FCC needs to make sure it's looking in all areas for spectrum, including broadcast spectrum.

>>>25 channels, assuming every other one can be used in an area, is still 12 channels.

False assumption. Where I live, because all the cities are packed closely together, they use every 4th channel. I made a list further below where you can see every channel from 2 to 51 is occupied by a TV station. That means if they cut back to 25 channels, then half the stations will need to be pulled off the air.

Where I live, because all the cities are packed closely together, they use every 4th channel. I made a list further below where you can see every channel from 2 to 51 is occupied by a TV station.

Wait, so is it every four channels occupied in a market or every channel 2 - 51?

So if two DC stations are using 22 and 26 (four apart, like you said) and adjacent markets are using 24 (so close together, you can't use adjacent channels, right), who's using 23 and 25 in your market?

>>>Wait, so is it every four channels occupied in a market or every channel 2 - 51?

DC, Baltimore, Philadelphia, Harrisburg is, in essence, one giant broadcast area. They all have to share the same 50 channels. Each city gets about 12-13 but all 50 are viewable by any single home, due to the overlap between cities. Using your hypothetical example:

Where I live (the Northeast Megalopolis) there are NO open channels. Every single channel from 2-51 is occupied by a TV station.

(sigh) I can easily imagine the kid next door turning on his "next gen wireless iPod or iPad" directly over top the Philadelphia or Baltimore sports game I'm trying to watch. Technically the FCC rules say I can order the kid to turn off his gadget, but that doesn't mean he would comply.

Cellphones currently have 600 megahertz of space.TV has 200. Let TV keep its space.

Try it in smaller range first. How many integers are there between 0 and 10? That's a small enough range that you can not only count them but also very easily list them: 1, 2, 3, 4, 5, 6, 7, 8, 9. Nine of them. 9 minus zero, or 10 minus 1, or 10-0 - 1.

Well in that case you're till wrong. Excluding 1000 and 1600 MHz, you can have a cellphone assigned 1000000000.1 Hz and another assigned at 1599999999.9 Hz, so that would be 599999999.9 Hz, or 599.9999999 MHz.

Or you could just not be anal and round it to 600 MHz, like I did in my original post.

Nope, 599 if you are rounding down, 600 if you're rounding normally. 1000MHz is 1,000,000,000Hz. 1600MHz is 1,600,000,000Hz. The space between these two points is 599,999,998Hz, which is 600MHz to a sane degree of rounding.

How on earth did you get out of college with an engineering or science degree?!?!? The SI unit "megahertz" can be applied to a discrete point (600 million cycles per second on the EM spectrum) - or - as a measure of bandwidth (700 through 1300 MHz == 600 megahertz of space). So going back to what I said:

- Cellphones have been assigned, by the FCC, approximately 600 megahertz of bandwidth- TV has been assigned approximately 200 megahertz of bandwidth

Perhaps I am to blame. Perhaps I wrote my sentence in shorthand (aka technospeak) but this IS slashdot after all - I expect technically-minded persons to understand the basics they learned in PHY101.

The space, added up from the variety of ranges they have, equates to a 600 MHz of bandwidth. That's 600 MHz of "space." So I don't understand what your complaint is, as it sounds just fine the way it worded.

No they did not. Analog 2-51 and Digital 2-51 are exactly the same spectrum. In fact a lot of the stations are had to do a "live cutover" from analog-to-digital at midnight June 12, because they occupy the exact same spot. These stations include WPVI, WGAL, WBAL, WHYY, WJZ, and so on..

>>>This is the whitespace formerly used by *ANALOG* broadcast TV.

Mistaken again. The former analog channels 52 through 69 have been sold to c

No they did not. Analog 2-51 and Digital 2-51 are exactly the same spectrum. In fact a lot of the stations are had to do a "live cutover" from analog-to-digital at midnight June 12, because they occupy the exact same spot. These stations include WPVI, WGAL, WBAL, WHYY, WJZ, and so on.

While that's technically true, ATSC also allows channels to be remapped - so what you see as "Channel 9" might actually be UHF channel 31.

Right here where I'm located (north Maryland). All 51 channels are assigned and used by TV stations, with overlap from DC, Baltimore, Harrisburg, and Philadelphia. The only one that's not occupied is 37 but that too is unusable by TV Band/whitespace Devices, because it's reserved for radio-astronomy.

The spectra weren't even used by analog broadcast TV. The spectra consist of unused space between the old channels, space that was left unused to avoid interference, harmonics, etc. between the analog channels.

there is no "space" between the channels, each TV channel is 6 MHz and with digital TV uses all of the allocated 6MHz. the FCC allocates every other channel in a market, but the TVBD rules do not allow the use of the "empty" channel next to any allocated TV transmitter. In the major markets the "empty" channels are all allocated to stations in the next near by citys. you can look at the northeast coast area( BOS-DCA), the upper mid west(MKE-CHI), San Fran, Los Angeles,... there is a broadcaster allocated

I find it disturbing that Slashdot Mods write +4 Informative on a post that's flat wrong. Digital TV is more efficient than analog tv was, and it uses the entire 6 megahertz channel. There's no room between channels. Each TV station butts-up against its neighbor like books on a shelf. No space inbetween.

Okay I just did a quick scan of my region, and here's all the occupied channels. Do you see any open spots for these TV Band/whitespace Devices? I don't. Also notice that many TV stations overlap simply because the FCC ran out of room!

Quoting myself: "Here is a list of all the occupied channels". In other words they all have TV broadcasts on them. Every single number listed in my last post is occupied by a Station broadcasting video.

As for your percentages above, they are not even close to accurate. Cities overlap. People can see TV stations from neighboring markets - in my case I can see 4 different markets, and sometimes even 5. So excluding isolated plac

So if the data doesn't fit your assumptions, you just cut it in half? Nice.

Methodology for the Trenton, NJ area:

"TV channel assignments were compiled using a variety of data sources to ensure accuracy. The preliminary channel line-up was taken from the Consumer Electronic Association's "Antenna Web" online resource (www.antennaweb.org), which lists all available signals from a given zip code. In this case, the base zip code used was downtown Trenton. CEA's listing was then cross-referenced with data from the Center for Public Integrity's Media Tracker Database (www.publicintegrity.org/telecom/) and the television license query engine at REC Networks (www.recnet.com/cdbs/fmq.php). All of these databases consist of information taken from the FCC. A final check was performed using the FCC's TV TVQ Database Query (http://www.fcc.gov/fcc-bin/audio/tvq.html). FCC databases were also searched to determine if any public safety organizations operated in the TV band. Channels with public safety devices were deemed occupied.

This combined station listing was cross-referenced with multiple local television guides to determine which channels are available over the air. All stations broadcasting in or near Trenton that can be viewed over-the-air in Mercer County were included."

The study admits its methodology is Flawed (like those studies claiming cellphones cause cancer are also flawed).

It only looked at the Trenton NJ market, and never bothered to look at neighboring cities like New York or Scranton, all of which *also* occupy space on the dial and "stretch" into the Trenton area. You cannot have TV Band/whitespace Devices broadcasting over those channels. When I look at that city using TVfool.com and a typical rooftop antenna, I see about 5 open channels. That's it. Everyt

> It only looked at the Trenton NJ market, and never bothered to> look at neighboring cities like New York or Scranton, all of which> *also* occupy space on the dial and "stretch" into the Trenton area

Really? Is that why all of those New York, Philadelphia, etc. stations (up to 57 miles away) are listed as occupied?

> When I look at that city using TVfool.com and a typical> rooftop antenna, I see about 5 open channels

Did you even click the link? Two channels are listed as occupied for public safety in the Trenton, NJ area.

Those channels aren't solely for public safety use, either, and aren't national. If public safety licenses existed in an area, those channels were marked as occupied. Richmond, VA area, for example, as TV stations on channels 14 - 19 and the methodology states

Seeing as how the channel allotment is artificially limited by the FCC these numbers mean little.

There are very few full power assignments available or at least not in the markets that anyone wants to be in. Sprinkle some LP, translator or other class A licenses around and it still doesn't add up to the capabilities of the technology. Even if you went to the effort to petition for a new license it wouldn't be guaranteed to be yours. It would then go through a bidding process available to all the vultures.

Are you arguing that there's only whitespace because of the artificial limitations the FCC puts on channel assignment? If they didn't have co-channel interference rules or geographic assignments, all of the channels be used by television broadcasters?

False. Channel allotment is limited by physical law. You can't have a channel 11 in Baltimore, and another channel 11 right next door in Washington or Richmond. The two stations would interfere with one another and the viewers would end-up seeing nada.

Actually, what he put down is quite accurate. If you live in Baltimore, you can actually receive the signals from all four of those markets. When they plan the TV stations, they take and draw a circle around the transmitter on a map of the size of the broadcast range for the particular channel, when circles intersect, the people in that overlap area won't receive either station as they will interfere with each other. As all those cities (except maybe harrisburg) are within 50 miles of each other, the ove

Let's see..... 2,3,4,5,6,8,9,10,11,12,13,14,15,16,17,18,19,20,21,24,27,29,31,33,35,36,37,41,42,44,45,48,49,51. Every one of these is a station I can view from my home, although some of them, like 6, only come-in after dark (the sun interferes with TV reception).

Just because *I* can't see a channel does not mean it's not being used for other purposes. For example I can't see Channel 7, but my neighbors ten miles to the east can.

Therefore channel 7 is NOT available for TV Band/whitespace Device usage in this spot. Ditto all the other channels. In fact the Official FCC Whitespace Database shows only *2* channels open 43 and 47 - but also forbid their use because they lie adjacent to existing TV stations.

And if a station is only viewable 10 miles away, that gives a five mile range (possibly) where a community system could be set up on these frequencies. Not all uses of this system are going to be 50 mile spheres (although I question the 50 mile range at only 4W EIRP).

In the end, maybe you are 100% correct. Your area will not be able to use these devices. At least the other 80% of the country can make use of them, though.

as I have seen you railing and railing on this over the whole thread, I decided to reply to this post. You obviously live in the same area I do, which is rather interesting, and you are posting on Slashdot, which means you are literate. I am a little baffled why you rail against this technology without even reading about it.

>>>These "wifi routers" are working in the white space between channels

You didn't get far. Only your second paragraph and already a blatant error. The TV Band/whitespace Devices broadcast ON channel (i.e. 13 through 51), not between channels. In fact it says that right in the article.

Furthermore there is NO space between television channels. Channels are like books on a shelf - they exist directly side-by-side. AND each channel is 6 megahertz wide - exactly the same width they were in the anal

You didn't get far. Only your second paragraph and already a blatant error. The TV Band/whitespace Devices broadcast ON channel (i.e. 13 through 51), not between channels. In fact it says that right in the article.

Did you bother to read the linked article? Let me help you out some:

ROSE: TV stations need licenses to use the airwaves. But the FCC wants to open up the so-called white spaces between channels so that tech companies can use them without a license. Genachowski says its the same approach that worked 25 years ago.

Unless you think the between there is wrong, but that is exactly what this person who works for a company that designs devices currently using this method says.

>>>between channels 1 and 6 there is a unused band of 14 khz

No. Not unused. It's occupied by various wireless services like police radio. Also 14 kHz isn't anything to get excited about. That's equivalent to a single AM station, and AM Digital Radio only broadcasts at 30 kbit/s...... slower than dialup internet. Completely worthless in the modern age. THINK.

I was speaking of the gaps in the bands of 802.11, if there are police radios up in the 2.4 Mhz range, that would surprise me greatly, as they wouldn't be much use. As to the speed issues you raise, the TV band with even a 14khz bandwidth is still pretty significant when you aggreg

Gott in Himmel! How the hell did you earn Bachelor of Science degree? You know *nothing* about basic radio broadcast or EM spectrum usage. Nothing. Which is fine - ignorance is acceptable. But I (and others) have told you time and time and time again THERE IS NO SPACE BETWEEN CHANNELS and still you refuse to hear what better-educated people are telling you. Like a stubbo

Allowing these devices to power up through a 50 mile radius basically speaks to the market the manufacturers are working toward.

These "white space devices" are going to be industrial-scale. They will cost tens of thousands of dollars and will have to be set upon a pretty tall tower or building to even be safe from an EMR standpoint.

It's not home networking. It's not even local area networking. This is a business model for Wireless ISPs that doesn't include an FCC licencing and application process.

50 miles requires a large antenna like the one I'm using now (4 by 3 feet) to receive a signal..... not really practical to attach on an iPod or iPad. 50 miles also requires a transmitter output of ~100,000 watts. That would drain a tiny iPad battery in about 1/4 minute.

Please stop posting about things you obviously know jack all about. You're thinking of broadcast FM stations where it's all about advertising revenue, where dumping more power in to the antenna directly relates to having more people that MIGHT be able to listen to your station, and it will certainly help the people at the fringe of your service area hear the advertisements better. VHF is line of sight only except in a few rare circumstances (tropospheric ducting and sporadic-E). 100,000 watts is hugely over

What do you think TV is? Answer: Computer data. If you want to send that computer data across 50 miles, you need at least 100,000 watts. By the time it reaches your home it's degenerated to only a few microwatts - just barely receivable by a larwe antenna (and not receivable at all with rabbit ears/loop).

WPMT-DT broadcasts at 933,000 watts.WPHL-DT is at 645,000 watts.WMPT-DT is 209,000 watts.

You've just agreed with the AC. I looked at the FCC data [fcc.gov] for WPMT [fcc.gov] - they are transmitting with 933 kW ERP, with ERP being the important difference - that stands for Effective Radiated Power, which takes antenna gain into account. The AC stated that using lower transmitter power coupled with large antennas on the tower are sufficient. I submit that WPMT is using a relatively high gain antenna to obtain the 933 kW ERP. This site says they have a transmitter putting out 20.2 kW with an 18.22 dB gain antenna [rabbitears.info].

>>>More power does NOT equal more distance; only antenna height will give more distance

This too is wrong. When WPVI-6 quadrupled its power, it also extended its range to double what it was before. It used to barely reach from Philadelphia to northeast Maryland, but now it reaches all the way to Baltimore. They didn't change their towers' height - only their transmitter power.

Both of you are correct to an extent. For high VHF and UHF frequencies, the propagation is fairly close to line-of-sight. That means that no amount of power will force RF to penetrate the earth beyond your radio horizon [wikipedia.org].

That said, receivers need a certain signal level to work properly. Until that level is exceeded at every point inside the radio horizon, additional power will help receivers that aren't seeing their minimum signal level. Once that level is reached for all points inside the radio horizon, add

This is similar to how you sometimes hear VHF FM Radio across multiple states - most of the power "escapes" into space but enough bends around the earth that it can be heard on the ground.

I'm an Amateur Radio operator and understand the concepts of tropospheric ducting and other propagation-related phenomena. You can't rely of any propagation mode other than line-of-sight at VHF or UHF frequencies. Even one of my favorite ham bands, 10m (~30 MHz) is slavishly reliant on the Sun for propagation. Right now it

The move to adopt white spaces for devices is expected to significantly accelerate adoption of wireless broadband because the low-frequency waves can travel through buildings and trees and cover a radius of 50 miles with a single router.

Quinn said new routers would leverage the larger coverage area to allow many more users to access the Internet for the same price as a standard W-iFi router. He predicted the earliest adopters would be college campuses, schools, libraries and other institutions that seek to provide ubiquitous Web access but have thick walls that make it difficult.

It *sounds* as if the technology is largely safe (because it's just wi-fi with more range) and is something that most places would invest in quickly. Sure it's not something you'd have at home, but exactly why would you need more square footage in the first place? It's not home networking because, unless you're living in a massive house or wanting to get your home wi-fi from your workplace, the nearby park, or a restaurant down the street, I don't understand why you'd

Think about it. Compare this mythical 50-mi radius super WiFi to an existing hotspot. Or cell tower, for that matter...

1 - Contention. how many clients will be in that coverage footprint, competing for the bandwidth. Radio is a shared medium - only one source can be using it at a time (disregarding exotic and expensive tricks). So you split it up into channels - there goes your bandwidth. And you MIMO the area into sectors - bummer if you live on a sector boundary and bounce between them. No matter what you do, you have to divide a limited resource among a whole lot of users. Suddenly, small local cells look a lot better.

2 - Power. Sure, your local TV station gets great coverage (or since digital, not so much). They've got a 50-Gazillion-Watt transmitter, and it's one-way. How much power will your laptop/tablet/phone/etc. need to talk reliably to a base station 50 *miles* away? At a decent data rate, with the interference of everybody *else* trying to get the attention of that base? It's hard enough to do on analog *voice* systems. If you thought hidden-node problems were bad with WiFi, you ain't seen nothing yet! Oh, and how big are the antennas going to have to be for these lower frequencies (compared to 2.4Ghz)? The next iPad will have a band around *it* for the antenna....

3 - Infrastructure. How many of these mega-APs will get to be in a given area? Does everybody get one (hey - no license)? It's not going to be easy or cheap to backhaul all of those clients from your huge central site. It's simple to serve a small area at a time, and the cell companies certainly have the hand-off issues worked out (well, mostly). But the only long-range two-way systems out there are fairly low-bandwidth and server relatively few nodes.

This will be good for places like large farms, disaster zones like Haiti, and other places where:

* The number of computers is small enough that bandwidth saturation is not an issue* The site has a sufficiently high tower and sufficient power to run the equipment* In a disaster scenario, there is a generator and a mast available* There is a "backhaul" Internet with sufficient bandwidth. In a disaster scenario this might be microwave or if latency isn't a problem, satellite.